Photoreceptor cells playing a role in human visual perception are particular subsets of retinal neurons and composed of rod cells and cone cells.
Rod cells contain the visual pigment rhodopsin that absorbs light, and the rod cells perceive the darkness of light (dark adaptation) using this rhodopsin.
Cone cells express photoreceptors capable of sensing red, green and blue wavelengths, and perceive the color of light depending on the extent of the response of the photoreceptors to the light absorbed by the eye.
As described above, the perception process by human vision is very complicated, and varies depending on the human emotional state.
As used herein, the term “physiologically active substance” refers to a substance that enhances or suppresses the function of a living body. A particular component of the substance can influence the biological function of the human body, and particularly, can also influence the visual perceptive function of the human body.
In other words, the fact that a physiologically active substance influences the visual perceptive function of the human body indicates that the physiologically active substance influences the biological function of the human body.
However, the development of a device or method for screening a physiologically active substance, which influences the biological function of the human body, based on the visual cognitive function of test animals, is still insufficient.